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61 Cards in this Set

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  • Back

What does the amount of mitochondria in a cell depend on?

The activity of cell. Liver and muscle cells have lots because they carry out multiple strenuous jobs and need more energy.

What is the function of ribosomes?

Protein synthesis

What is a gene?

-section of a chromosome made DNA

-codes for a particular protein

Explain the structure of DNa

Two strands coiled to form a double helix, each strand containing chemical bases. Each gene has different bases. A, T, C, G are the bases and their sequence determines what protein is made bc the codes for the amino acids are in the sequence.

How does DNA leave a cell?

A copy is made of the sequence in the nucleus and is carried out by messenger RNA/ mRNA

What did Watson and Crick (1953) do?

Built a model of DNA using data from other scientists; this data included x-rays showing the double helix and data indicating the bases occurred in pairs.

Name some functions of proteins?

Structural: collagen

Hormones: insulin

Carrier proteins: haemoglobin

Enzymes: ...enzymes

Explain catalyst reactions (respiration, photosynthesis, protein synthesis)

The enzyme grabs on to the substrate at the active site. Catalysis happens:the substrate is changed. It could be broken down or combined with another molecule to make something new. It will break or build chemical bonds. The enzyme then releases the product.

Explain the optimum enzyme conditions

-Moderate temperatures for high collision rate but not denaturing

-Moderate pH because at too high/low the active site changes shape and the substrate can't fit.

When should you calculate the co efficient?

When finding the temperature that alters rate of reaction

Reasons for and consequences of mutations?

-Spontaneously caused or due to radiation or chemicals

-Lead to production of different enzymes

-Often harmful

-Occasionally can give an advantage! Nice one

How to mutations cause the production of a different enzyme?

Rearrange base pairs

Chemical equation for aerobic respiration?

C6H12O6 + 6O2 => 6CO2 + 6H2O

Why does anaerobic respiration happen?

Muscles aren't receiving sufficient oxygen

Word equation for aerobic respiration?

glucose => lactic acid (+ energy)

Disadvantages to anaerobic respiration?

-Lactic acid causes pain and fatigue

-Releases less energy than aerobic

-Incomplete breakdown of glucose results in oxygen debt

Why do breathing and heart rates stay high when recovering from oxygen debt?

-Rapid blood flow carries lactic acid to liver

-Extra oxygen supplied, enabling liver to break down the acid

How can you measure the rate of respiration?

-Measuring how much oxygen is used up, faster consumption means faster rate

-Rate at which CO2 is made

How do you calculate the respiratory quotent?

CO2 produced / Oxygen used

What is the metabolic rate?

The sum of all reactions occurring in the body.

What are the advantages to becoming multicellular?

-Allows an organism to become larger and more complex.

-Different cells take different jobs (cell differentiation)

What systems are needed when organisms become multicellular?

-allow communication between cells

-supply cells with enough nutrients

-control exchanges with the environment such as heat and gas

What is mitosis?

Asexual reproduction to make 2 identical daughter cells

What is meiosis?

Asexual reproduction to make 4 haploid, unidentical cells

What happens during mitosis?

-4 double stranded chromosomes unzip to be singular strands

-These strands form an X shape then a spindle forms and single strands move to poles of the cell

-They're pulled apart from the centre to form 2 new cells

What happens during meiosis?

-Single strands are copied to form Xs

-Each X moves to the poles

-Xs are pulled apart leaving one strand in each corner

-4 new haploid cells form (all genetically different from each other)

Process to make 2 identical daughter cells is..?


Process to make 4 unidentical cells is?


What is a diploid cell and who has them?

Mammals have them and they are cells with two copies of each chromosome.

What type of cell division makes gametes?


How is sperm adapted to its job?

-Many mitochondria for energy

-Acrosome to release enzymes to digest egg membrane

What is plasma and what is its function?

The liquid part of the blood

Carries dissolved food substances, carbon dioxide, hormones, antibodies and waste such as urea

How are red blood cells adapted to their purpose?

-Small so they can pass through the smallest blood vessels

-Biconcave: large surface area to exchange oxygen quicker

-Haemoglobin to combine with oxygen

-No nucleus so more haemoglobin can fit

How is oxyhaemoglobin made?

When haemoglobin reacts with oxygen in lungs. It's reversible though as oxygen is released in tissues.

What are the jobs of these:




Arteries: transport blood away from heart to tissue

Veins: transport blood back to the heart from tissues

Capillaries: link arteries to veins to allow materials to pass between the blood and tissues

How are arteries, veins and capillaries adapted to function?

Arteries: thick/elastic walls to resist high pressure

Veins: large lumen/valves to keep the blood moving back to the heart bc pressure is low

Capillaries: permeable walls so substances can be transferred between blood and tissues

Process of the heart?

Blood comes from lungs through the pulmonary vein, pumped through the left atrium/bicuspid valve through the aorta to the rest of the body. OR Vena Cava brings deoxy. blood from body through right atria/tricuspid valve out pulmonary artery to lungs.

What is the benefit of a double circulatory system?

Higher pressure for further pumping ;;)));;)

Why is the left ventricle thicker than the right?

More pumping power to get blood to the whole body.

What do plant cells have that bacteria don't?

Mitochondria, nucleus and chloroplasts.

Where is bacteria's DNA?

In the cytoplasm as a singular circle strand chromosome.

When are the two stages of rapid growth in kids?

Just after birth and in adolescence.

Where can stem cells be obtained from?


Why are embryonic stem cells better than adult stem cells?

They can form a greater range of cell types and are easier to find.

Differences between plant and animal growth?

-Animals tend to grow to a set size but plants can just keep going

-Plant cell division only occurs at meristems

-Plants gain height mainly by cell elongation rather than division

-Many plant cells keep the ability to differenciate

What and where are meristems?

The sites of plant cell division, found at the tips of roots and shoots.

What is the problem with selective breeding?

Inbreeding. 2 closely related animals are bred together which reduces the variety of alleles in the population and can lead to increased risk of harmful recessive traits and also less variation so they can't adapt to change quick.

What are the adv and disadv of genetic engineering?
+Organisms with desired features produced quickly!

-Inserted genes may have unexpected harmful side affects

Name some examples of GM organisms.
-Rice that contains Beta-Carotene originally from carrots. The BC is then turned into Vit A in body.

-GM bacteria that produces insulin

-Pesticide resistant crops

What are the ethical issues involving GM?
-Worry that GM things will disturb natural ecosystems

-Morally wrong

Explain the process of Genetic Engingeering
-Desired characteristics selected

-Genes responsible are identified and removed (isolation)

-Genes inserted into other organisms

-Organisms are allowed to reproduce

What is gene therapy?
Using genetic engineering to change a person's genes and cure certain disorders.
What is a gamete?
A mature sex cell
What is a haploid cell?
A cell with a single set of unpaired chromosomes.
Changing genes in gametes is controversial because?
It can lead to designer babies.
How was Dolly the sheep cloned?
Using nuclear transfer.

-Egg taken from sheep A

-Cells taken from udder of sheep B

-Nucleus of sheep B put in to egg from sheep A

-Complete cell given electric shock to start reproducing and put into surrogate mother

Why do we clone organisms?
-Mass produce animals with desirable characteristics

-To make animals to provide human products

-Produce human embryos for stem cells.

How are plants cloned?
Process called tissue culture.
Explain the process of cloning plants.
-Plant is selected that has certain characteristics

-Large number of small pieces of tissue are cut

-Pieces are grown in test tubes with growth medium

-Aseptic technique used to stop microbes infecting plants

Why is cloning plants easier than cloning animals?
Because some cells retain the ability to differentiate in plants whereas animal cells lose this quickly.

Explain the process of DNA fingerprinting

Isolation - separate the DNA from other tissues

Fragmentation - use an enzyme to break the DNA into short lengths

Separation - pass an electric current across a layer of gel which has the DNA fragments at one end. The fragments will move different distances across the gel. This is called gel electrophoresis

Comparison - match the pattern of fragments on the gel with other samples of DNA